Fix OAuthSignatureCalculatorInstance switched query and form params, close AsyncHttpClient#1540

Motivation:

OAuthSignatureCalculatorInstance#computeSignature switched form and
query params parameter when calling signatureBaseString.

Modification:

Fix parameters order.

Result:

Valid OAuth signature

Author: slandelle

client/src/main/java/org/asynchttpclient/oauth/OAuthSignatureCalculatorInstance.java

@@ -110,8 +110,8 @@ String computeSignature(ConsumerKey consumerAuth,
       userAuth,
       uri,
       method,
-      queryParams,
       formParams,
+      queryParams,
       oauthTimestamp,
       percentEncodedNonce);